This invention relates to a system for monitoring various conditions of fluid-containing members, particulary inflatable members such as vehicle tires. More particularly, this invention pertains to monitoring systems that include a valve assembly that controls fluid flow into or out of the fluid-containing member and contains an energy source that is accessible without deflating or dismantling the fluid-containing member.
It is well known that various conditions of vehicle tires should be monitored to enhance the safety, comfort, and economy of driving the vehicle. Such conditions include the internal temperature and pressure, the wear of the tread, and the expiration date assigned by the manufacturer. Several systems to monitor conditions such as pressure in vehicle tires have been disclosed in the prior art. Two types of such systems have been described in U.S. Pat. No. 4,609,905. The first type is the direct reading of fluid pressure in a tire wherein sealed rotating fittings or electrical slip rings are used in the interface between the wheel and the vehicle body. A second type is the transmission of fluid pressure information through an inductive or magnetic coupling. A third type is the use of radio frequency transmitters and receivers which use radio waves to communicate data between the vehicle tire and the driver in the vehicle.
The radio frequency transmitter is typically affixed to each vehicle tire and operates in conjunction with a receiver located on the vehicle body. The transmitter is preferably inside the tire to avoid being exposed to damage from weather and physical shock. Regardless of its location, the transmitter requires electrical energy for its operation. The energy source is typically a battery. Since the transmitter is located inside the tire, the replacement of any energy source within the transmitter requires the inconvenience of dismounting the tire from the vehicle, deflating the tire and removing the rubber section from the rim section.
This problem has been addressed in several ways in the prior art. Monitoring systems in which the energy source is located outside the vehicle tire as part of the transmitter are disclosed in GB 2279169 and WO 91/04874. However, such systems are susceptible to damage from weather, dirt, and physical shocks. Other systems with energy sources inside the tire are designed to use minimal amounts of electrical energy to extend the useful life of the energy source. However, energy sources such as batteries typically last less than twelve months even with long periods of low or no activity. If the energy source fails prematurely, replacement requires dismounting the tire from the vehicle and deflating the tire.
The problem of providing electrical energy to an electrical device inside the tire by means of a conveniently replaced energy source has not been solved by the systems of the prior art.
The present invention relates to a valve assembly that controls the fluid flow into or out of a fluid-containing member, particularly inflatable members such as a tire. The valve assembly includes an energy source that is conveniently accessed without dismounting the tire from the vehicle or deflating the tire. At the same time, the energy source is protected against weather, dirt or other hazards. The valve assembly can also include an electrical device such as a transmitter that can be positioned inside the fluid-containing member.
The valve assembly according to the present invention includes two valve sections, an inner valve section and an outer valve section that cooperate to control the flow of a fluid into or out of a fluid-containing member such as a vehicle tire. The inner valve section controls the flow of fluid in and out of the fluid-containing member at or near the entry point of the fluid. The outer valve section is outside the fluid-containing member. The outer valve section cooperates with the inner valve section to control the fluid flow in and out of the fluid-containing member.
The valve assembly of the present invention is typically part of an electric circuit that can be mounted on a support plate that can be part of or attached to the base of the inner valve section. An preferred embodiment of the valve assembly includes a transmitter module as part of the electric circuit. The transmitter module can be mounted on a support plate that is part of or attached to the base of the inner valve.
More particularly, the present invention relates to a valve assembly that includes a main body member having a passageway extending there through, an outer body member having a passageway extending there through and which is connected to a first section of the main body member, an insulating member having a passageway extending there through and which is connected to a second section of main body member. The passageways of the main body member, outer body member and insulating member cooperate to define a continuous passageway for fluid flow wherein the insulating member includes an inner valve that engages the insulating member so as to control fluid flow into or out of the continuous passageway and the outer body member includes an outer valve that engages said outer body member so as to control fluid flow into or out of the continuous passageway.
The valve assembly according to the present invention can also contain an electrical energy source operatively connected to the inner valve and the outer valve. The inner valve and the outer valve cooperate with the energy source to form an electrical circuit. During normal use of the valve assembly according to the present invention there is no change in the procedure for adding or removing fluid currently employed with valves that are well known in the art. Unlike known valves, the valve assembly of the present invention also permits the user to remove and replace the energy source without emptying or dismantling the fluid-containing member.
A system for monitoring conditions inside a fluid-containing member such as a tire includes the valve assembly according to the present invention, an energy source, a transmitter module located inside the fluid-containing member for transmitting signals related to various conditions and a receiver module for receiving transmission of the signals from the transmitter module for communicating information to the user regarding the various conditions inside the fluid-containing member.
The valve assembly according to the present invention permits convenient removal and replacement of the energy source without disturbing the fluid state in the fluid-containing member. There is no the need to empty, open, or dismantle the fluid-containing member in order to replace the energy source. This is particularly convenient when the fluid-containing member is a vehicle tire. By being located between the valve components, energy source is protected from hazards such as water, dirt, and physical forces. The diameter of the energy source is such that fluid flows around the energy source. When the valve assembly is used in a tire, the energy source can be replaced without deflating the tire or even dismounting the tire from the vehicle. The inner valve seals the air inside the tire when the energy source is removed. Once the energy source is replaced, the outer valve again seals the air inside the tire.
These advantages are achieved while adhering to ISO standards for car tire valves and permitting normal procedures typically performed by the user. Even though the valve assembly contains the energy source, the valve assembly complies with ISO standards for valve dimensions in car tires. The tire can be filled or deflated by typical means such as an air pump since the inner valve is opened when the outer valve is opened. The fluid flows around the energy source, through the open inner valve, and into the tire.